George Plimpton, the self-deprecating author of “Paper Lion” and other sporting adventures and a patron to Philip Roth, Jack Kerouac and countless other writers, has died. He was 76.

Plimpton died Thursday night at his Manhattan apartment, his longtime friend, restaurateur Elaine Kaufman, said Friday. She had no information on the cause.

…He boxed with Archie Moore, pitched to Willie Mays and performed as a trapeze artist for the Clyde Beatty-Cole Brothers Circus. He acted in numerous films, including “Reds” and “Good Will Hunting.” He even appeared in an episode of “The Simpsons,” playing a professor who runs a spelling bee.

…In “Paper Lion,” he documented his time training with the Detroit Lions in 1963. Allowed briefly to play quarterback, he remembered the crowd cheering as he left the field after a series of mishaps.

“I thought about the applause afterward. Some of it was, perhaps, in appreciation of the lunacy of my participation and for the fortitude it took to do it,” he wrote, “but most of it, even if subconscious, I decided was in relief that I had done as badly as I had.

“It verified the assumption that the average fan would have about an amateur blundering into the brutal world of professional football. He would get slaughtered. … The outsider did not belong, and there was comfort in that being proved.”

His other books included “Bogey Man,” “Out of My League” and “Shadow Box.” Plimpton could also take credit for at least one memorable fictional character: Sidd Finch, a baseball pitcher of unprecedented gifts (168 mph fastball) and unlikely background (reared in the mountains of Tibet) portrayed so vividly by Plimpton in a 1985 Sports Illustrated article that many believed he existed.